Occult hepatitis B virus (HBV) infection is of concern in human immunodeficiency virus (HIV)-infected persons. We observed that 2% of 400 HIV-infected women with antibodies to hepatitis B core antigen alone had occult HBV infection (i.e., detectable HBV DNA in the absence of HBV surface antigen). CD4 cell counts of <200 cells/mm3 were more common among occult HBV-infected women than among those without occult HBV infection. Aminotransferase levels did not appear to be associated with being positive for HBV DNA.